Below is the description taken straight from MERCK
on this media used in manufacturing the meningococcal
vaccine.
Cat. No.
1.05437.0500/5000
(500 g, 5 kg)
Merckoplate® MUELLER-HINTON
Agar
Cat.No. 1.10414.0001
(20 plates, 20 ml each)
Merckoplate® MUELLER-HINTON
Agar
Cat.No. 1.13405.0001
(480 plates, 20 ml each)
Media proposed by
MUELLER and HINTON (1941) for testing the sensitivity of clinically important pathogens
towards antibiotics or sulfonamides.
These culture media
comply with the requirements of the WHO (1961, 1977) and DIN Norm 58930.
MUELLER-HINTON agar is used for agar diffusion tests while MUELLER-HINTON broth is
employed for the determination of the MIC in serial dilution tests.
Mode of Action
The composition of the culture media provide
favourable growth conditions, the media are almost totally devoid of sulfonamide
antagonists.
In order to improve the growth of fastidious microorganisms, blood can be added to
MUELLER-HINTON agar. According to JENKINS et al. (1985), this may lead to false results
when testing the susceptibility of enterococci to aminoglycosides.
Preparation
and storage Cat. No. 1.05437 MUELLER-HINTON Agar (500 g/5 Kg) Usable
up to expiry date when stored dry and tightly closed at +15 to +25 °C. Protect from
light. After first opening of the bottle the content can be used up to expiry date when
stored dry and tightly closed at +15 to +25 °C.
Suspend 34.0 g/litre,
autoclave under mild conditions (10 min at 115 °C), if required cool to 45-50 °C and add 5-10 % definibrated blood, pour
plates.
pH: 7.4 ± 0.2 at 25 °C.
Without blood, the plates are clear to opalescent and yellowish-brown.
Cat.No. 1.10414.0001 Merckoplate®
MUELLER-HINTON Agar (20 plates, 20 ml each)
Cat.No. 1.13405.0001 Merckoplate® MUELLER-HINTON Agar (480 plates, 20 ml each) Ready-to-use,
microbiologically controlled.
Usable up to the expiry date when stored at +12 to +15 °C.
The plates are clear to opalescent and yellowish-brown.
Experimental Procedure
and Evaluation
Carry out the sensitivity or resistance test as
directed.
Incubation for 24 h at 35 °C aerobically.
Quality control of
MUELLER-HINTON Agar
Inhibition
zone diameter in mm acc. to WHO (revised)
TEST
STRAINS
Test discs
Esch. coli ATCC 25922
Staph. aureus ATCC
25923
Pseud. aeruginosa ATCC
27853
Enteroc. faecalis ATCC
33186
Ampicillin 10 µg
15-20
24-35
-
-
Tetracyclin 30 µg
18-25
19-27
-
-
Gentamicin 10 µg
19-26
19-27
16-21
-
Polymyxin B 300 IU
12-16
7-13
-
-
Sulfamethoxazole 1.25
µg +
Trimethoprim 23.75 µg
24-32
24-32
-
16-23
Quality control of
MUELLER-HINTON Broth
Test
strains
Growth
Escherichia coli ATCC
25922
good / very good
Staphylococcus aureus
ATCC 25923
good / very good
Pseudomonas aeruginosa
ATCC 27853
good / very good
Enterococcus faecalis
ATCC 33186
good / very good
Bacillus subtilis ATCC
6633
good / very good
(Antagonist test!)
Streptococcus pyogenes
ATCC 12344
good
Streptococcus
pneumoniae ATCC 6301
fair / good
Listeria monocytogenes
ATCC 19118
fair
Literature
BAUER, A.W., KIRBY,
W.M.M., SHERRIS, J.C., a. TURCK, M.: Antibiotic susceptibility testing by a standardized
single disk method. - Amer. J. Clin. Pathol.,
45;
493-496 (1966).
DIN Deutsches Institut für Normung: Methoden zur Empfindlichkeitsprüfung von
bakteriellen Krankheitserregern (außer Mycobakterien) gegen Chemotherapeutika.
Agar-Diffusionstest. - DIN 58940.
ERICSSON, H.M., a. SHERRIS, J.C.: Antibiotic Sensitivity Testing. Report of an
International Collaborative Study. - Acta path. microbiol.
scand., B. Suppl., 217; 90 pp (1971).
JENKINS, R.D., STEVENS, S.L., CRAYTHORN, J.M., THOMAS, T.W., GUINAN, M:E., a. MATSEN,
J.M.: False susceptibility of enterococci to aminoglycosides with blood-enriched
Mueller-Hinton agar for disk susceptibility testing. - J. Clin. Microbiol., 22; 369-374 (1985).
MUELLER, H.J., a. HINTON, J.: A protein-free medium for primary isolation of the
Gonococcus and Meningococcus. - Proc. Soc. Expt. Biol.
Med., 48;
330-333 (1941).
World Health Organization: Standardization of methods for conducting microbic sensitivity
tests (Technical Report Series No. 210, Geneva 1961).
World Health Organization: Requirements for antibiotic susceptibility tests. I. Agar
diffusion tests using antibiotic susceptibility discs. (Technical Report Series No. 610,
Geneva 1977).
The word agar comesb
from the Malay word "agar-agar" meaning jelly. It was in 1881 that Robert
Koch showed the value of agar in culturing bacteria, and imported the stuff from
Japan which had a monopoloy on the agar trade until 1940...
Agar is a compound in its own right. It is a polysaccharide
found in the cell walls of some red algae and is unusual in containing sulfated galactose
monomers. It requires nothing but extraction and purification to become agar, but is
sometimes chemically modified into agarose for special applications. Agar added to media
simply gels them into a convenient solid form.
